


An Exercise in Necessity

by ifwegettherebysunset



Category: Yu-Gi-Oh!
Genre: Anzu is a Gift, Dates, Fluff, Getting Together, Holding Hands, Humor, Kissing, M/M, Polyamory
Language: English
Status: Completed
Published: 2020-02-11
Updated: 2020-02-11
Packaged: 2021-02-28 02:07:21
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,891
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/22665994
Author URL: https://archiveofourown.org/users/ifwegettherebysunset/pseuds/ifwegettherebysunset
Summary: To make a relationship work, you have to compromise. Or, Seto brings Yugi in by necessity, and finds out that Yugi's actually not so bad.
Relationships: Atem/Kaiba Seto, Atem/Kaiba Seto/Mutou Yuugi, Atem/Mutou Yuugi, Kaiba Seto/Mutou Yuugi
Comments: 16
Kudos: 123





	An Exercise in Necessity

**Author's Note:**

> at first i put in all the yami yugi/"" tags and it looked like a MESS and i'm like y'know what it's the same person let's just do the atem/""
> 
> i am physically and emotionally exhAUSted y'all who else in the club. when I'm exhausted like this i apparently have ENDNOTES D: so uh sorry bout that but ya the numbers peppered in here aren't mistakes

_"If I win, you come back with me."_

* * *

When Atem takes Seto's hand and crashes back into the world, they reach an unspoken agreement to duel each other as often as they can. Eventually, they take to eating either before or after, depending on when Seto's schedule permits, usually at Seto's place or near an arena for convenience.

At some point, they reach another unspoken agreement, in that Atem may kiss him. Mokuba's the one who says _dating_ first, smiling at his big brother: it's as if, right before his eyes, Seto's come back to life more than Atem.

So they're dating. In a relationship. Not too difficult a leap for Seto as it would have been Before, when he hadn't had to go a year without Atem standing across from him. Atem stutters a bit at the start of every date, no matter how many they've had, but he regains his footing within a minute. Because it's Seto. They _know_ each other. _"_ _Parce que c'était lui; parce que c'était moi,"_ and all that.(1)

But it's clear from the start that Atem is never completely present.

* * *

"Um. Sorry. _What_?"

Seto glares at Yugi, looking completely out of place in the humble game shop. Yugi's sure he's grown at least two feet since he'd first charged in for the Blue-Eyes, but maybe he's projecting.

"You heard me."

"No, I did." Yugi shakes his head. "I'm just _v_ _ery_ confused."

Seto rolls his eyes. "I think I made myself clear."

"Kaiba, you just told me you want me to join you and Atem on your date. I don't think you have."

Seto's lip curls. "He won't stop looking around for you. If you're there, he can focus."

Yugi blinks slowly. "Focus on...you?"

" _Yes_."

Yugi stares blankly at the counter top, where his hands rest limply. "How...how exactly would that help?"

"Are you not listening?"

"Give me an example. When you say he keeps looking for me?"

Seto scoffs, eyes snapping to a tournament poster. Everything about him is tense, slightly curled around his crossed arms. But the answer comes freely enough: "We were at dinner last night." They're already having lunch today. "He said he was interested in the new Black Magician cards. He looked to his right and stopped talking, like he was expecting someone to answer."

Yugi's heart clenches. "Me."

Seto zeroes back on him. "You." A beat. "So?"

And Yugi should really say no. With Anzu's going to America, he's been left to face the full force of whatever the hell had ignited between him and Seto _and_ whatever the hell had been simmering between him and Atem. It's like a trainwreck love song, only it's his _life_. Accompanying them on a date of all things is outrageous in itself.

But he also knows exactly how Atem feels. He thought he'd stopped looking around too. Physically, he fell out of the habit, but sometimes he still finds himself fishing around in his head for that other presence. He and Atem string their thoughts together without even being connected as they were. Soon enough he'll be back in the habit.

Maybe...

Oh, no fucking way is he thinking of saying—

"Okay."

What the _hell_.

Seto's eyes gleam. "Good. Atem knows where we'll be. Follow him."

Before he can leave, Yugi calls, "Have you told him about this?"

Seto makes a dismissive wave. The door's bell rings cheerfully behind him.

Yugi scrubs his hands down his face.

* * *

Atem is delighted. Yugi is hesitant. Seto, after careful observation, is satisfied.

Yugi doesn't talk much, but he finishes Atem's thoughts before Atem can do another annoying head turn or fall into bewildered silence. They can finally carry a damn conversation.

When it comes time to duel, Yugi offers to leave. Seto brushes that off. It's irritating that Atem needs another to be fully with him, but there's clearly no getting around it. The pros outweigh the cons.

So Yugi stays at Atem's side. They don't talk during the duel, but Seto can tell how the slightest gesture communicates volumes between them. He lets it slide; it's how they dueled for four years anyway.

He wonders, as they play, if that's what his AI had been missing. For all that Yugi shows Atem's influence, Seto hadn't considered the element of _Yugi_ that makes Atem who he is. "Not one, but truly two."(2)

Regardless, _this_ is the Atem he knows.

When Isono parks near Kame, Yugi politely excuses himself before Atem and Seto say their goodbyes. The moment the door closes, Atem cups Seto's cheek.

"Thank you," he murmurs. "I thought I'd realized just how much I'd missed him, but—well. Thank you."

He leaves him with a deep kiss.

* * *

Yugi becomes a regular guest. The downside is his schedule sometimes differs, so they can't always have fulfilling dates. They stop going on dates if Yugi's not there. Seto gets Yugi's number for correlation.

For his part, Yugi knows this is getting _way_ out of hand. He's having the time of his life. They may not have the Puzzle anymore, but he can tell just by the way Atem breathes what he's thinking. These duels have no stakes, and they're against Kaiba, his favorite opponent besides Jounouchi. Seto is a master of the game, and so expressive when he's wielding his disk. When they duel, Yugi gets to see Seto as he really is, and—fuck, he loves what he sees: the uninhibited challenger with a shine in his eyes.

He needs advice.

* * *

"Are you pranking me?"

Anzu doesn't sound like she actually believes that.

"No," Yugi replies.

"...Yugi. _Yugi_."

"I _know_."

"No offense, but I don't think you do. You've turned into—"

"—a love song?"

"Yeah, we'll go with that." Anzu sighs. "Okay. So you're dating them."

"No!" Yugi winces. His grandfather's trying to sleep. "No. Um, I'm just kinda—a tag-along."

"No you're not."

"...um?"

Anzu can't help laughing. "Here's my advice: duel Kaiba yourself."

"But it's his and Atem's date!"

"You'll see what I mean, okay? Trust me."

Yugi stares at her. There's sunlight to her right; it's ten in the morning over there. She looks beautiful. Like she's where she's supposed to be.

"This would've been a lot easier if I'd asked you out," he blurts, immediately smacking a hand over his mouth and apologizing.

Anzu's a little pink too, but she's smiling genially. "Yeah, but you always like to make things difficult for yourself."

* * *

"Hey, Atem?"

They're holding hands again. Somehow, they always end up doing it.

"Hm?"

Yugi catches his eye.

Atem grins and nods.

With renewed confidence, Yugi says, "Kaiba."

Seto raises an eyebrow.

"When we get to the arena—I'm dueling you this time."

At first, Yugi thinks he's going to say no. His eyes narrow; he looks between the two of them.

Then he grunts, faces forward, and says, "Interesting. Fine."

Excitement bubbles, squeezing Atem's hand. Atem squeezes back, swinging their arms a little.

Yugi really hopes he doesn't get used to this.

* * *

Dueling Yugi is inherently different. Seto had seen from their previous duel that his skill has grown exponentially, and he of all people can appreciate coming from nothing. Yugi doesn't wear his jacket like a cape, nor does he posture or puff his chest. He fights like a shield with a hidden spike: every move is calculated, steely. He plays the long game and plays it well.

Even so, he enjoys himself.

Atem is a beacon of pride. He watches Yugi like a fawning zealot, giving little to no cues as Yugi had done when he was dueling. Sometimes Yugi will glance at him and they'll smile at each other. Sometimes Yugi will look at Seto and smile at him.

Yugi wins.

"That was awesome, Seto!" he cries, beaming, "Thanks!"

It was, Seto realizes. He'd had fun too. There's a different kind of charged passion than when he duels Atem, but it's no less invigorating. He doesn't _need_ to duel Yugi again, but he _wants_ to.

How much time Seto had wasted in that year without, exclusively dueling an AI.

* * *

The first sign Seto notes is how he reacts to Yugi's challenging smile. It's the smile he'd shown when Seto stood against Diva: exhilarated, yet hardened. When he asks Seto for a duel, it comes out, and something in Seto's chest burns.

The second sign is how Atem begins to react. He looks between them with dilated pupils. He and Yugi haven't dueled each other yet—the Ceremonial Duel is still a fresh wound—but he seems enraptured by Yugi and Seto's games.

Seto watches, catalogues, and comes to a conclusion. It's a fascinating one that his teenage self would have recoiled from. He almost can't believe it himself.

But the conclusion stands, so he asks Atem to come to his penthouse alone.

* * *

"Are you _sure_? What if he..."

"Do you seriously not see the signs. You're joined at the hip."

"What signs?"

Oh for fuck sake. If you want something done right.

"Are you in or not?"

Atem gives a breathless "Yes."

He ends up following Seto out with rumpled clothes.

* * *

Something's different.

Atem is practically vibrating at his side. They're not going to eat. Seto is looking at him strangely.

By the time they reach Kaiba Dome, Yugi's half out of his mind with nerves.

"What's up?" he asks. "Something wrong?"

"Not at all!" Atem replies quickly.

"We have something to ask you," Seto says.

Yugi's heart pounds. "Sure."

"Would you like to join our relationship?"

Yugi chokes.

Just. Right out with it. That's Seto, though.

Um.

"Aibou?" Atem murmurs, squeezing his hand in both of his.

Yugi glances between them with wide eyes. "You're—you're not joking with me, right?"

Atem looks appalled. Seto looks unimpressed.

"I'm just. It's a surprise. I mean—you _both_ want—?"

"Yes," Atem replies instantly. He cups Yugi's cheek. "Yes."

Yugi turns to Seto. "And...you, too?"

Seto crosses his arms, practically looking at him down his nose. "I wouldn't've asked if I didn't."

Holy shit.

_Ho_ ly _shit_.

He's a fucking love song.

Slowly, Yugi reaches out. Seto's heartbeat is a little fast under his palm. He rises to his tip-toes; Seto bends.

Yugi has absolutely no experience outside of a one night's practice with Anzu when they were pre-teens, but it's not hard to catch on. Seto keeps it simple, closed-mouth. He smells like cologne and the leather of his coat. He's firm and sure of himself, straightforward as always.

Behind him, Atem strangles a desperate noise. Yugi jolts as he fits himself to his back, face pressed into the shoulder Seto's not white-knuckling. They all sway slightly with him. As soon as Seto breaks their kiss, Yugi's pulled into another.

Kissing Atem is a more frenzied thing. Those four years reach their boiling point in the span of seconds, Atem wrapping around his waist, gripping his face. Yugi scrambles to grab his wrists and hold on until they can both calm down. With every twitch, Atem reads how he wants to move, and oh fuck, it's like he's a teenager again, how the hell does he move his tongue, fuck it doesn't matter this is _fantastic_ —

When they finally part, panting heavily, Seto's eyes are nearly black.

"So?" Seto grunts.

Yugi smiles his challenging smile. "Yes. Of _course_ yes."

**Author's Note:**

> (1) a Completely Heterosexual Thing Montaigne, a French writer, said in an essay about his buddy and their Deep Heterosexual Bond.  
> (2) Jekyll & Hyde. Can't remember if the quote is from the original story or the ITV Jekyll and Hyde (that deserved better). Even though ITV's version has Jekyll and Hyde essentially being two different entities when they're really, really not, but I'm not getting into that here lmao I still love that damn show
> 
> I wrote this during class. So uhhhhhhhh sorry if my writing suffered


End file.
